Peak occupancy of transcriptional activators at gene promoters occurs in the middle of the day and corresponds with a peak in H3K9acetylation. Peak transcription occurs shortly after nightfall, as indicated by activated RNA polymerase binding. Transcriptional repressor occupancy peaks shortly thereafter, and corresponds with a peak in Hk34 tri-methylation. Additional transcription factors and co-factors, such as CRY1 and CBP appear to occupy promoters at different times, and poised RNA polymerase occupancy peaks just at the end of the 24-hour cycle (Based on data from (Koike et al., 2012) and figure from (Takahashi, 2017)).